Specify internal_network_name

This allow one to specify a specific internal network name for the case
where there is more than one nic on an instance. Without this, the list
of ports may not return the correct order. Therefore, it is necessary
to specify the exact internal network to attach the floating ip to

library/cloud/quantum_floating_ip

@@ -75,6 +75,11 @@ options:
         - The name of the instance to which the IP address should be assigned
      required: true
      default: None
+   internal_network_name:
+     description:
+        - The name of the network of the port to associate with the floating ip. Necessary when VM multiple networks.
+     required: false
+     default: None
 requirements: ["novaclient", "quantumclient", "neutronclient", "keystoneclient"]
 '''
 
@@ -82,7 +87,7 @@ EXAMPLES = '''
 # Assign a floating ip to the instance from an external network
 - quantum_floating_ip: state=present login_username=admin login_password=admin
                        login_tenant_name=admin network_name=external_network
-                       instance_name=vm1
+                       instance_name=vm1 internal_network_name=internal_network
 '''
 
 def _get_ksclient(module, kwargs):
@@ -135,7 +140,13 @@ def _get_server_state(module, nova):
         module.fail_json(msg = "Error in getting the server list: %s" % e.message)
     return server_info, server
 
-def _get_port_info(neutron, module, instance_id):
+def _get_port_info(neutron, module, instance_id, internal_network_name=None):
+    if internal_network_name:
+        kwargs = {
+            'name': internal_network_name,
+        }
+        networks = neutron.list_networks(**kwargs)
+        subnet_id = networks['networks'][0]['subnets'][0]
     kwargs = {
             'device_id': instance_id,
     }
@@ -143,9 +154,16 @@ def _get_port_info(neutron, module, instance_id):
         ports = neutron.list_ports(**kwargs)
     except Exception as e:
         module.fail_json( msg = "Error in listing ports: %s" % e.message)
+    if subnet_id:
+        port = next(port for port in ports['ports'] if port['fixed_ips'][0]['subnet_id'] == subnet_id)
+        port_id = port['id']
+        fixed_ip_address = port['fixed_ips'][0]['ip_address']
+    else:
+        port_id = ports['ports'][0]['id']
+        fixed_ip_address = ports['ports'][0]['fixed_ips'][0]['ip_address']
     if not ports['ports']:
         return None, None
-    return ports['ports'][0]['fixed_ips'][0]['ip_address'], ports['ports'][0]['id']
+    return fixed_ip_address, port_id
 
 def _get_floating_ip(module, neutron, fixed_ip_address):
     kwargs = {
@@ -204,7 +222,8 @@ def main():
             region_name                     = dict(default=None),
             network_name                    = dict(required=True),
             instance_name                   = dict(required=True),
-            state                           = dict(default='present', choices=['absent', 'present'])
+            state                           = dict(default='present', choices=['absent', 'present']),
+            internal_network_name           = dict(default=None),
         ),
     )
 
@@ -219,7 +238,7 @@ def main():
     if not server_info:
         module.fail_json(msg="The instance name provided cannot be found")
 
-    fixed_ip, port_id = _get_port_info(neutron, module, server_info['id'])
+    fixed_ip, port_id = _get_port_info(neutron, module, server_info['id'], module.params['internal_network_name'])
     if not port_id:
         module.fail_json(msg="Cannot find a port for this instance, maybe fixed ip is not assigned")